One of Britain’s fattest pupils turned his life around by losing 70kg (11st) and is now setting up as a fitness coach thanks to a government grant.

Nathan Hewitt weighed 146kg (23st) at 15 but after burning off nearly half his weight, the 23-year-old now wants to help other obese children in his home town of Merthyr Tydfil, south Wales.

The low point for the super-slimmer came when he was turned away from a roller-coaster ride at Alton Towers because the safety bar wouldn’t fit over his girth.

‘I knew at that moment I had to change my life for good,’ he explained. ‘My weight was making me miserable.’

Nathan Hewitt, 23, is now one of Merthyr Tydfil’s most eligible bachelors (Picture: Wales News Service)

So despite a childhood of binging on junk food and playing video games the twenty-something will now set up his own fitness firm thanks to a £6,000 Young Entrepreneur’s Business Grant from the Welsh government.

‘I’ve been there, I know how it feels to be massive. You only have to look at my old photographs to see I was huge,’ explained Mr Hewitt.

The Welshman says he feels like a completely different person compared to his teenage self and losing weight has increased his confidence, health and fitness.

‘A lot of obese children don’t think they can make the changes they need to lose weight but I’m there to show them they can,’ he added.